FEATURED NEW PRODUCTS

what they are
New Akt Pathway Phospho and Total 7-Plex Magnetic Panels provide accurate quantitation of 7 proteins in cell lysates and tissue homogenates. These panels are suitable for use with the Luminex® 200™, FLEXMAP® 3D, and MAGPIX® systems.

how they work
Samples are mixed with magnetic beads of defined spectral properties conjugated to analyte-specific capture antibodies, and incubated for 2 hours. After binding, a magnet can be used for easy washing similar to ELISA washing. Analyte-specific biotinylated detector antibodies are then added and incubated with the beads for 1 hour. During this second incubation, the analyte-specific biotinylated detector antibodies recognize the epitopes and bind to the appropriate immobilized analytes. After removal of excess biotinylated detector antibodies, streptavidin conjugated to the fluorescent protein R-phycoerythrin (RPE) is incubated for 30 minutes. After washing, the beads are analyzed using a Luminex® instrument to quantify all 7 analytes.

what it is
The Image-iT® Fixation/Permeabilization Kit contains all of the necessary reagents to prepare your cells for antibody staining and imaging. The high-quality components help preserve cell morphology and reduce background staining, and are provided in a convenient storage box in single-use vials with easy-to-follow protocols.

how it works
Cells are treated sequentially with the fixative, the permeabilization solution, and the blocking buffer according to a simplified and easy-to-follow protocol. The reagents are optimized to preserve 3D cellular structure and provide adequate antibody access to intracellular antigenic sites. The high-quality components and optimized formulations help decrease background staining, improving signal-to-noise levels and image quality. In extensive testing with both nuclear and cytoplasmic targets, the reagents provided in this kit offered results equal or superior to those from standard reagents.

what it is
Ki-67 is a large (~360 kDa) nonhistone protein that is associated with, and may be required for, cell proliferation. Ki-67 protein is not detected in the G0 phase of the cell cycle but is detected in steadily increasing amounts from the G1 phase through mitosis. Ki-67 accumulates beginning in late G1 and is localized in small granules throughout the nucleus. We now offer Ki-67 ABfinity™ Recombinant Rabbit Oligoclonal Antibody for cell cycle studies.

NEW APPLICATIONS

The Tali® Image-Based Cytometer is a valuable tool for routine cell analysis, delivering quantitative data right at your benchtop. In two recent application notes, we demonstrated the versatility of the Tali® Image-Based Cytometer in moving beyond fluorescent protein or viability detection to quantitative analysis of cell cycle and caspase-3/7 activation.

As described in the first application note, quantitative detection of S-phase cells was accomplished using the Click-iT® EdU Alexa Fluor® 555 reagent and the red channel of the Tali® instrument. Mitotic arrest (M phase) was detected using anti-phosphohistone H3 antibody, an Alexa Fluor® 488 secondary antibody, and the green channel of the Tali® instrument. As described in the second application note, apoptotic cells were detected and accurately counted using CellEvent® Caspase-3/7 Green Detection Reagent and the green channel of the Tali® instrument.

PROVEN PERFORMER

The recommended protocols for many fluorescently labeled affinity proteins require diluting the conjugate to a working concentration, and then using the resultant solution immediately. When the diluted solution is not used immediately, performance may become less optimal over a period of hours, depending on the concentration, container material, and buffer formulation. A common laboratory practice for stabilizing diluted solutions is to add minimally interfering carrier proteins. This strategy can also be used to stabilize solutions containing diluted fluorescently labeled proteins.

For example, the fluorescence signals from diluted solutions of fluorescent Qdot® 655, Alexa Fluor® 488, and R-phycoerythrin streptavidin conjugates diminish dramatically over 3 hours in a polystyrene 96-well microtiter plate when diluted in 1X PBS alone. However, adding 1% bovine serum albumin (BSA), 10% fetal bovine serum (FBS), or 10% goat serum (GS) to the buffer dramatically stabilizes the solutions, and fluorescence intensity is maintained for at least hours. Using this technique can help researchers obtain brighter and more consistent fluorescence labeling.

DEPARTMENTS

On the Web

Benchtop Devices—Simple Solutions to Everyday Complexities

Discover how easy it can be to count cells, quantitate DNA, or even perform PCR. Watch as Luca, a precocious preschooler, demonstrates the use of the Countess® Automated Cell Counter, Qubit® 2.0 Fluorometer, and Veriti® Thermal Cycler.

From the Bench

Finding the Connections Between Oxidative Stress and DNA Replication

If not repaired, DNA damage caused by H2O2 and other oxidants accumulates over time and contributes to aging, cellular senescence, and predisposition to disease. In a recent publication, Zhao and colleagues presented results from a study to determine the correlation between damage response events and DNA replication. The researchers pulse-labeled cells with EdU and then exposed them to H2O2. Incorporated EdU was detected using an Alexa Fluor® 488 dye–labeled azide, and multiparameter laser-scanning flow cytometry and confocal microscopy were employed to identify DNA-replicating cells and examine the location of DNA replication sites. Using this approach, the researchers were able to see a close association between DNA replication and damage response events, and postulated that these events may be triggered by stalled replication forks and possibly by induction of DNA double-stranded breaks at the sites of H2O2-induced damage. Detecting incorporated EdU using click chemistry made it possible to identify cells that are replicating their DNA and to examine other intracellular epitopes at the same time.